This invention is generally directed to toner and developer compositions, and more specifically, the present invention is directed to developer and toner compositions containing novel polyester-imide resins, and process for the preparation thereof. In embodiments, there are provided in accordance with the present invention, toner compositions comprised of polyester-imide resins, and pigment particles comprised of, for example, carbon black, magnetites, or mixtures thereof, cyan, magenta, yellow, blue, green, red, or brown components, or mixtures thereof thereby providing for the development and generation of black and/or colored images. In embodiments, there are provided in accordance with the present invention toners with economical polyester-imide resins of the following formula, and which imides can be prepared by melt condensation processes ##STR2## wherein R is an alkylene, and more specifically an oxyalkylene or a polyoxyalkylene, wherein alkylene contains, for Example, 1 to about 20 carbon atoms, such as diethylene oxide, triethyleneoxide or polyoxypropylene, and R' is alkyl or alkylene containing, for example, from about 1 to about 25 carbon atoms; and wherein n represents the number of segments, thus n can be a number of from about 5 and preferably 10 to about 10,000. The toner compositions of the present invention in embodiments possess a number of advantages such as low cost, low melting characteristics, excellent blocking characteristics, high glass characteristics, excellent admix characteristics, excellent nonvinyl-offset properties, and low relative humidity sensitivity such as from about 1.01 to about 2.3. The polyester-imide resin of the present invention can in embodiments be generated by a process involving the melt polycondensation of about 0.95 to about 1.05 mole equivalent of anhydride such as a trimellitic anhydride, from about 0.45 to about 0.55 mole equivalent of a diol such as ethanediol or 1,2-propanediol, and of from about 0.45 to about 0.55 mole equivalent of an alkylene diamine, or preferably diaminoterminated alkylene oxides such as the diamino terminated polypropylene oxide or diaminoterminated polyethylene oxide available from Texaco Chemicals as JEFFAMINE D-230.TM., D-400.TM., D-700.TM., EDR-148.TM., EDR-192.TM., and it is believed as illustrated by the formula ##STR3##
The aforementioned polyester-imides exhibit in embodiments, for example, a number average molecular weight of from about 1,500 to about 50,000, and preferably about 20,000 grams per mole as measured by vapor phase osmometry, and possess a glass transition temperature of from about 40.degree. C. to about 80.degree. C., and more preferably from about 50.degree. C. to about 65.degree. C. as measured by the Differential Scanning Calorimeter, and an M.sub.w of from about 2,500 to about 100,000.
Specifically, in embodiments, the present invention is directed to toner compositions comprised of a pigment, charge control agent and the polyester-imide resins as illustrated herein, and which toners possess low fixing of from about 120.degree. C. to about 140.degree. C., high gloss such as from about 50 gloss units to about 80 gloss units as measured by the Garner Gloss metering unit, nonvinyl offset properties and in addition low relative humidity sensitivity such as from about 1.0 to about 2.0. These and other advantages are attained by the toner compositions of this invention comprised of a pigment, optionally a charge control agent and a polyesterimide resin derived from a trimellitic anhydride, a diol and organodiamine, which compositions exhibit low fixing temperature characteristics of from about 120.degree. C. to about 140.degree. C., high gloss such as from about 50 gloss units to about 80 gloss units, nonvinyl offset properties, and low relative sensitivity such as from about 1.0 to about 2.3.
Examples of advantages of the toner composition of the present invention comprised of polyester-imide include the enablement of low fusing temperatures, such as from about 120.degree. C. to about 140.degree. C., and therefore lower fusing energies are needed for image and toner fixing thus enabling less power consumption during fusing, and permitting extended lifetimes for the fuser system selected. Furthermore, the toner composition of the present invention in embodiments possess a broad fusing latitude such as from about 40.degree. C. to about 100.degree. C. with a minimal amount or avoidance of release oil, which oil inhibits the toner from offsetting onto the fuser rollers usually associated with ghosting or background images on subsequent copies. Furthermore, the fused image obtained from the toner composition of the present invention in embodiments does not substantially offset to vinyl covers, such as those utilized for notebook binders, and possess a low humidity sensitivity ratio of from about 1 to about 2.3 as calculated by the ratio of the triboelectric charge in microcoulombs per gram of the developer after placed in a chamber of 20 percent humidity for 48 hours, to the triboelectric charge in microcoulombs per gram of the developer after placed in a chamber of 80 percent humidity for 48 hours.
In designing resins for toner composition, it is generally desired that the glass transition temperature of the resin be from about 50.degree. C. to about 65.degree. C., and preferably no less than about 55.degree. C. so that, for Example, the toner particles do not aggregate, coalesce or block during the manufacturing, transport or storage process or until the toner is required for the electrophotographic, especially xerographic, fixing step. Additionally, low fusing characteristics are required, hence the resin should melt or flow at a low temperature such as from about 120.degree. C. to about 145.degree. C. Moreover, low relative humidity sensitivity of toners, such that the triboelectric charge is stable to changes in environmental humidity conditions, is of importance.
Illustrated in the following copending applications, the disclosures of each being totally incorporated herein by reference, are:
U.S. Ser. No. 144,075, illustrates a toner composition comprised of a pigment and a crosslinked polyimide; and wherein the crosslinked polyimide can be obtained from the reaction of a peroxide with an unsaturated polyimide of the formula ##STR4## R is alkyl or oxyalkylene and m represents the number of monomer segments present and is a number of from about 10 to about 1,000.
U.S. Ser. No. 144,435, illustrates a toner composition comprised of a pigment, and a thermotropic liquid crystalline polyimide of the formula ##STR5## wherein m represents the number of monomer segments present; X is a symmetrical moiety independently selected from the group consisting of phenyl, naphthyl, cyclohexyl, or bicycloaliphatic; and R is independently selected from the group consisting of alkyl, oxyalkylene and polyoxyalkylene.
U.S. Ser. No. 144,956, illustrates a toner composition comprised of pigment, and polyimide of the formula ##STR6## wherein n represents the number of monomer segments, and is a number of from about 10 to about 1,000; and R is alkyl, oxyalkyl, or polyoxyalkyl.
U.S. Ser. No. 144,918, illustrates a toner composition comprised of pigment, and polyimide of the formula ##STR7## wherein m represents the number of monomer segments present; X is ##STR8## thus X can be benzophenone, oxydiphthalic, hexafluoropropane diphenyl, diphenyl sulfone, or biphenyl; and X is attached to four imide carbonyl moieties; and R is independently selected from the group consisting of alkyl, oxyalkylene and polyoxyalkylene.
The present invention enables toners with high gloss, low fusing temperatures, and low relative humidity sensitivity and the resins of the present invention are of lower cost then those of the copending applications based on information estimates utilizing the Chemical Marketing Reporter.
Polyimide resins, liquid crystalline polyimide resins, and, more specifically, polyester-imide resins are also known such as summarized and illustrated in the Encyclopedia of Polymer Science and Engineering, 2nd Edition, Volume No. 12, published by Wiley (1985). However, these polyimide resins are aromatic and useful as high performance materials, and are not, it is believed, useful for toner applications, and additionally polyester-imide resins with flexible diamino alkane moieties and, more specifically, polyoxyalkylene moieties are not mentioned.